This patch allows to simulate the lost of frames exchanged between the 2
nfcsim devices through a control entry in the debugfs and is used as
follow:

 echo n > /sys/kernel/debug/nfcsim/nfcX/dropframe

Where n specifies the number of frames to be dropped between 0 and 255
and nfcX is either nfc0 or nfc1, one of the two nfcsim devices.

In the following example, the next frame that should be sent by the nfc0
device will be dropped and thus not received by the nfc1 device:

 echo 1 > /sys/kernel/debug/nfcsim/nfc0/dropframe

The value of 0 can be used to reset the dropframe counter.
Signed-off-by: NThierry Escande <thierry.escande@collabora.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

The idea is to have a way to control and/or modify the behavior of the
nfcsim virtual devices.

This patch creates a folder tree in the debug filesystem. The debugfs is
usually mounted into /sys/kernel/debug and the nfcsim entries are
located in DEBUGFS/nfcsim/nfcX/ where X is either 0 or 1 depending on
the device you want to address.

These folders are empty for now and control entries will be added by
upcoming commits.
Signed-off-by: NThierry Escande <thierry.escande@collabora.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

With this complete rewrite, the loopback nfcsim driver now relies on the
Digital layer of the nfc stack. As with the previous version, 2 nfc
devices are declared when the driver is initialized. The driver supports
the NFC_DEP protocol in NFC-A and NFC-F technologies.

The 2 devices are using a pair of virtual links for sk_buff exchange.
The out-link of one device is the in-link of the other and conversely.

To receive data, a device calls nfcsim_link_recv_skb() on its in-link
and waits for incoming data on a wait queue. To send data, a device
calls nfcsim_link_send_skb() on its out-link which stores the passed skb
and signals its wait queue. If the peer device was in the
nfcsim_link_recv_skb() call, it will be signaled and will be able to
pass the received sk_buff up to the Digital layer.
Signed-off-by: NThierry Escande <thierry.escande@collabora.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

added the rx delay parameter as a device tunable parameter.
Signed-off-by: NSaurabh Sengar <saurabh.truth@gmail.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

In order to manage in a better way the nci poll mode state machine,
add mode parameter to deactivate_target functions.
This way we can manage different target state.
mode parameter make sense only in nci core.
Signed-off-by: NChristophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

Use a more standard kernel style macro logging name.

Standardize the spacing of the "NFC: " prefix.
Add \n to uses, remove from macro.
Fix the defective uses that already had a \n.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

Use the generic kernel function instead of a home-grown
one that does the same thing.

Add \n to uses not at the macro.  Don't add \n where
the nfc_dev_dbg macro mistakenly had them already.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

This patch fixes 3 sparse warnings:
nfcsim.c:63:25: sparse: symbol 'wq' was not declared.
nfcsim.c:484:12: sparse: symbol 'nfcsim_init' was not declared.
nfcsim.c:525:13: sparse: symbol 'nfcsim_exit' was not declared.
Reported-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NThierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

This driver declares two virtual NFC devices supporting NFC-DEP protocol.
An LLCP connection can be established between them and all packets sent
from one device is sent back to the other, acting as loopback devices.

Once established, the LLCP link can be disconnected by disabling the target
device (with rfkill, nfctool, or neard disable-adapter test script).
Signed-off-by: NThierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>